+ return lazy(get_value, str)()
+
+
+@register.inclusion_tag('social/carousel.html', takes_context=True)
+def carousel(context, slug):
+ # TODO: cache
+ try:
+ carousel = Carousel.objects.get(slug=slug)
+ except Carousel.DoesNotExist:
+ # TODO: add sanity check for install.
+ carousel = None
+ banners = [
+ item.get_banner()
+ for item in carousel.carouselitem_set.all()
+ ]
+
+ request = context['request']
+ if 'banner' in request.GET:
+ try:
+ banner_id = int(request.GET['banner'])
+ except (TypeError, ValueError):
+ pass
+ else:
+ try:
+ index = [b.pk for b in banners].index(banner_id)
+ except ValueError:
+ if request.user.is_staff:
+ # Staff is allowed to preview any banner.
+ try:
+ banners.insert(0, Cite.objects.get(pk=banner_id))
+ except Cite.DoesNotExist:
+ pass
+ else:
+ # Put selected banner to front.
+ banners = [banners[index]] + banners[:index] + banners[index+1:]
+
+ return {
+ 'carousel': carousel,
+ 'banners': banners,
+ }
+
+
+@register.inclusion_tag('social/embed_video.html')
+def embed_video(url):
+ m = re.match(r'https://www.youtube.com/watch\?v=([^&;]+)', url)
+ return {
+ 'youtube_id': m.group(1) if m else None,
+ }